19. Scientists experiments to make sure the results are meaningful.
a. perform
b. repeat
C. conclude
d. communicate

  B.

Explanation:

this is how scientists make sure they did there steps correct

answer: if she breaths she a thho

explanation:

sheep is a herbivore animal whereas grasshopper belongs to the class chordates but both of them feed on greens.  

if grasshopper and sheep feeding on a pasture land, i do not think both of them will have any impact on each other. however, the number of the species can make difference. since sheep feed on greens, there is a possibility there left no pasture land for the grasshoppers or they may get extinct.